Sustained-tone piano



Dec. 31, 1929. F. MUNGER 1,741,948

SUSTAINED TONE PIANO Filed April 5, 1926 2 Sheets-Sheet l WW" WW M De. 31, 1929. F. MUNGER 1,741,948

SUSTAINED TONE PIANO Filed April 5, 1926 2 Sheets-Sheet 2 M WM/"m Patented Dec. 31, 1929 UNITED STATES PATENT OFFICE SUSTAINED-TONE PIANO Application filed April 3, 1926f semi No. 99,518.

This invention relates to musical instruments and especially to pianos, piano players, or other instruments employing a large number of vibratory strings each having a fixed pitch.

The main object of the invention is to provide a highly efficient sustained tone piano or analogous musical instrument wherein the strings may be continuously and uniformly vibrated for the length of time desired.

It is another object of the invention to provide an attachment or action which may be substituted for the standard action on a piano to convert the same into a sustained 1 tone instrument without reorganization of the parts thereof.

A. further object is to provide in such a de vice a plurality of independently controllable revoluble exciting members adapted to uniformly and continuously vibrate the several strings as desired to produce sustained tones, said exciting members all being driven from a single source of power.

Another object is to provide a sustained tone action for a standard piano having means for vibrating the several strings and for also operating the dampers simultaneously therewith.

It is a more specific object in such a device 0 to provide a plurality of revoluble exciting members all driven from a common driving member and each adapted to engage one of the several strings and mounted in swingable arms capable of being manipulated by the keys.

A still further object is to provide in such a device transmission mechanism from the common driving member to the exciting discs whereby said discs may be mounted to extend in planes normal with the several strings of a piano. 7

These and other objects of the invention will be apparent from the following description made in connection with the accompanying drawings, wherein like characters refer to similar parts throughout the several views, and in which Fig. 1 is a fragmentary plan view of a grand piano with the top removed and with my invention applied thereto.

Fig. 2 is a vertical section showing one of the action units or key units complete, taken on the line 22 of Fig. 3, and

Fig. 3 is a fragmentary plan View of my invention as applied to two of the ordinary piano strings.

In the drawings the invention is shown applied to a grand piano of standard type, although of course the same will have equal applicability to upright pianos or other analogous musical instruments employing a plurality of vibratory strings each having a fixed pitch.

In Fig. 1 a portion of the foundation of a grand piano is illustrated comprising the case the sounding board 5, the frame 6, the usual iron plate 7 to which the strings are adjustably secured for tuning, and the usual white and black keys indicated by the numerals 8 and 9 respectively, fulcrumed in the key bed 10 (see Fig. 3) in the usual manner. Each of the keys 8 or 9 is mounted on the fulcrum 11 secured thereto in operative position by means of balance rail pins 12.

Lower strings 13 are stretched across frame 6, obliquely disposed with reference to the sides of case at, and upper strings 1 1 are likewise mounted in the usual manner crossing lower strings 13 centrally thereof and disposed some distance thereabove.

I provide a novel sustained tone action which may be substituted for the standard action employed in most pianos and which may be readily removed from the key bed for cleaning or repair. A relatively heavy transverse rail 15 is employed extending across and beneath the strings 13 and 14.- and disposed forwardly of the line on which the strings are engaged and vibrated. Rail 15 carries on its upper side an elongated channel member 16 having journaled in the ends thereof the worm 17 also extending beneath all of the strings of the piano. A motor 18 of suitable type is secured adjacent one end of channel member 16 and is connected by belt or chain 19 to drive worm 17. A series of relatively short spaced transverse shafts 20 are ournaled in the sides of channel member 16, there being one of said shafts for each of the strings of the piano. Each of shafts carries a worm gear 21 in mesh with worm 17 and constantly driven thereby when the motor 19 is run. The inner ends of shafts 20 project beyond the inner side of channel member 16 and are connected by universal joints 18 to a second series of shafts 22, each journaled in a swingable arm 23. Arms 28 terminate at their ends adjacent channe. member 16 in forks 23 which are hinged to brackets 24 carried on the inner side of channel member 16. The arms 23 may thus be swung in a vertical plane and obviously may be hinged to channel member 16 to swing in planes parallel with the obliquely disposed strings. This is essential for the proper oper ation of the device as will be later seen.

To manipulate arms 23 by means of the keys 8 and 9 I provide upright bars 25 having dowel pin engagement at their lower and upper ends with the inner extremities of keys 8 and 9 and with apertured tongues 23 carried by arms 23. A seat 25 is provided in the upper end of each of bars 25 and a coiled spring 26 is interposed between seat 25" and the under side of tongue 23 on each of said arms 23. A second coiled spring 27 is employed in each action unit secured at one end to channel member 16 and at the other end to a depending arm of lug 23 on the arm 23. Obviously springs 27 normally and yieldingly hold the arms in downward position.

To excite or vibrate the strings 18 and 14 I provide a plurality of discs 28 each keyed or otherwise secured to one of the shafts 22 journaled in the swingable arms. These discs may be of any suitable construction to properly vibrate the strings but are preferably formed on a base of elastic material such as rubber over which horsehair or some other relatively hard, flexible member is wound. Since the shafts 22 are of necessity spaced rather closely together I arrange my discs 28 011 the shafts 22 in staggered relation whereby exciting members of larger diameter may be employed. It will be seen that in normal position the exciting discs 28 lie slightly below the strings 13 and 14 and will be swung upward into engagement therewith when the respective keys are depressed by the artist. The parts are so arranged and the arms 23 so mounted, which is possible because of the universal joints 18, that the arms 23 will be aligned with their respective strings and the discs 28 will be moved against their respective strings with said strings extending normalthereto when contact is made.

My action also includes means for simultaneously operating the usual dampers 29 for the springs. I accomplish this simply by providing damper rods or wires 30 connected to dampers 29 and curved about the strings and extending downwardly through apertures in a guide rail 31 transversely mounted across the piano foundation. The lower ends of damper rods 30 are bent outwardly at right angles to the body portions thereof extending through apertures or seats 25 formed in the intermediate portions of upright bars 25. It will be seen that when keys 13 and l l are depressed not only will engagement be made between the exciting members 28 and the strings, but moreover the dampers 29 will be lifted simultaneously.

Operation The operation of the above described device may be briefly summarized as follows:

The several exciting members 28 are constantly driven when the motor 18 is run and will be swung against the appropriate strings when the respective keys are depressed. It will be seen that the strings 13 and 14 will be continuously and uniformly vibrated as long as the keys are depressed, producing the desired sustained tones. Through the action of springs 27 the arms 23 are quickly and noiselessly lowered as soon as the keys are released, thus making it pos sible to obtain short tones and staccato notes when desired. Gravity, the balance on the k ys 8 and 9, and the effect of springs 27 cooperate to return the keys to normal position and simultaneously disengage exciting members 28 and cause dampers 29 to contact the strings.

In a piano of either grand or upright type the upper and lower strings are crossed at their intermediate portions, thereby requiring shafts 22 to be swingably disposed at an angle to the shafts 20. Moreover, the several strings in both the upper and lower sections are not exactly parallel but vary in their spaced relations. By employing a universal joint in each of the units having one of its pivots approximately aligned with the pivot of its arm 23, I am able to mount my units in proper alignment with the several strings, and provide for the swinging there of.

The small springs 26 interposed between the inner ends of arms 23 and bars 25 provide a yielding action when the strings are engaged by the exciting members 28, which will compensate for wear and small irregularities in the mounting and construction of the several units.

It will be obvious that the entire action may be removed from the forward end of the piano in the usual manner, the several parts being mounted on the rail 15 and slidably disposed within the key bed.

From the above description it will be apparent that I have invented a practical and efficient sustained tone piano or action for a standard piano capable of wide general usage and adapted to vibrate the several strings continuously and uniformly for the length of time desired.

It will of course be understood that various changes may be made in the form, details, proportions and arrangement of parts without departing from the scope of the in-' vention.

\Vhat is claimed is:

1. In combination with a fulcrumed key of a piano and its appropriate vibratory string, a driving shaft extending transversely of said string and adapted to be connected with a source of power, an arm extending longitudinally of said string having its end adjacent said driving shaft pivoted on an axis extending transversely of said string, a rotary exciting member mounted in said arm on an axis disposed longitudinally of said string, a permanent flexible driving connection between said exciting member and said shaft, and a connection between the inner end of said key and the non-pivoted end of said arm adapted to cause said arm to move in the direction of said string when the outer end of said key is depressed whereby said exciting member may be made to engage said string.

2. In combination with the fulcrumed keys of a piano and their corresponding vibratory strings, a sustained tone action comprising an elongated driving shaft extending transversely of said strings and adapted to be connected to a source of power, a series of spaced arms, each extending longitudinally of one of said strings, said arms being pivoted at their ends adjacent said shaft on axes extending transversely of said strings, a series of rotary exciting members mounted in said arms, permanent flexible driving connections between said exciting members and said shaft, connections between the inner ends of said piano keys and the free end of said arms to cause said arms to move in the direction of said strings when their appropriate keys are depressed, thereby causing said exciting members to engage said strings, and means for yieldingly holding said arms away from said strings.

3. In combination with a fulcrumed key of a piano and its corresponding vibratory string, a sustained tone action comprising a driving shaft extending transversely of said string and adapted to be connected to a source of power, an arm extending longitudinally of said string and pivoted at its end adjacent said shaft, a rotary exciting member mounted in said arm on an axis extending longitudinally of said string, a permanent flexible driving connection between said exciting member and said shaft, a connection bar having one of its ends engaging the inner end of said key and having its other end engaging the free end of said arm to cause said arm to move in the direction of said string when the outer end of said key is depressed, whereby said exciting member will engage said string, and means for yieldingly holding said arm away from said strin 4;. In combination with a fulcrumed key of a piano and its corresponding vibratory string, a sustained tone action comprising a driving shaft extending transversely of said string and adapted to be connected to a source of power, an arm extending longitudinally of said string and pivoted at its end adjacent said shaft, a rotary exciting member mounted in said arm on an axis extending longitudinally of said string, a permanent flexible driving connection between said exciting member and said shaft, a connection bar havin g one of its ends engaging the inner end of said key and having its other end engaging the free end of said arm to cause said arm to move in the direction of said string when the outer end of said key is depressed Whereby said exciting member will engage said string, and a damper member carried by said bar and disposed on the side of said string opposite said arm and adapted to engage said string when said key is in normal position.

i In testimony whereof I affix my signature.

FRANCIS MUNGER. 

